Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/28/22
Area Forecast Discussion
National Weather Service Indianapolis IN
932 PM EST Sun Nov 27 2022
.Forecast Update...
Issued at 932 PM EST Sun Nov 27 2022
Current surface analysis reveals low clouds across the state in the
wake of an area of low pressure pulling off to the northeast. 02Z
IND ACARS soundings shows saturation in the lower levels with dry
air beginning to advect in above 700mb. Despite some holes in the
low stratus, most areas will remain socked in with clouds and patchy
drizzle through Monday morning. An approaching upper ridge and
surface high should work to lock in moisture near the surface as a
low level inversion sets up overnight. A weak upper wave passing by
overnight may have enough lift/energy with it to wring out left over
moisture resulting in scattered areas of drizzle among the low
clouds. Therefore added drizzle wording to the overnight and early
morning forecast for all of Central Indiana.
Low clouds are expected to stick around through the morning hours
Monday then gradually lift and begin to break up during the
afternoon. Low sun angle this time of year may take a longer time
heating the boundary layer, leading to moisture staying trapped
under the inversion longer. Due to the increase in clouds, lowered
max temperatures tomorrow toward NBM 25th percentile for highs.
&&
.Short Term...(This evening through Monday)
Issued at 300 PM EST Sun Nov 27 2022
* Damp...Raw and Windy Finish to the Holiday Weekend
* Cloudy and Dry for Monday
Low pressure has now tracked into north central Indiana with colder
air beginning to spill into the Wabash Valley as winds veer to the
northwest. Highs have been reached across the entire area
already...with temperatures falling back into the 40s for the rest
of the day.
Initial focus will be on an increasingly raw and chilly airmass as
scattered light showers and pockets of drizzle through the rest of
the afternoon as the surface wave shifts northeast away from the
region. In the wake of this system...quasi-zonal flow aloft and a
weak surface ridge will become the primary features influencing
weather across the Ohio Valley for Monday.
For the rest of the afternoon...expect periodic drizzle and
scattered light rain showers as the bulk of the deeper forcing
associated with the surface low pulls away from the region. Cold
advection will become increasingly prevalent as low level flow veers
to northwest across the forecast area through early evening. Gusty
winds will remain an issue over the next several hours as well with
the cold advection and steep low level lapse rates present. But the
core of the low level jet which had aided in the stronger winds
earlier is in the process of moving out of the forecast area and
into Ohio. This should keep gusts lower than what we experienced in
many parts of the forecast area this morning. Expect peak gusts of
30-35mph to largely be the norm into the early evening before slowly
dropping off as the surface pressure gradient relaxes.
Most of the precipitation should be out of the forecast area by 00Z
but cannot rule out a few lingering light showers across the
northeast extending out through much of the evening. While some
scattering of the lower stratus may swing across the lower Wabash
Valley this evening...expect clouds to remain over much of the
forecast area through the night as the low level inversion
establishes. The presence of the low clouds should also limit fog
overnight. The inversion will remain on Monday and with low level
winds weakening as the surface ridge axis drifts across the
area...potential is there for the stratus to have a lot of
difficulty in mixing out most if not all day. There are hints that
the arrival of ridging aloft late day may be enough to scatter the
low clouds over western counties but in general...expect mainly
cloudy skies to be the rule on Monday for most of the forecast area.
Temps...temperatures will drop back into the 35 to 40 range across
the region tonight as cold advection persists. Temperature recovery
will be limited by the clouds Monday with low level thermals
supportive of mid to upper 40s for most.
&&
.Long Term...(Monday night through Sunday)
Issued at 305 PM EST Sun Nov 27 2022
* Marginally strong/severe winds possible Tuesday night in
thunderstorms mainly south/west of Terre Haute/Bloomington
* Otherwise strong gusts to 30-40 MPH expected Tuesday Afternoon
thru late Wednesday
Monday Night through Wednesday...
The long term will start amid the, albeit brief, return to dry
conditions as rather weak high pressure settles over the eastern
CONUS as the next storm system strengthens near Colorado. The
resultant surface gradient and southerly winds will increase during
the day Tuesday as the surface low ejects to near the Quad Cities
area. Winds will gust as high as 30-40 MPH through the PM hours as
rain chances increase ahead of the system`s approaching cold front.
A solid fetch of Gulf moisture will boost precipitable water values
over 1.00 inch for about 12-hr near the overnight hours...when high-
POPs with isolated to scattered thunder are expected to cross
essentially all counties. Precipitation chances will return for an
approximately 24-hour period centered around Tuesday night. Most
recent guidance is showing the supporting upper wave trending
slightly more intense...with, despite near-zero surface-based
instability, a threat of elevated convection, mainly from Terre
Haute to Bloomington and especially points south. Damaging winds
would be the main threat, although details surrounding this
nocturnal concern will be refined in future updates. Rainfall
potential will be equal to or less than this weekend`s recent
rainmaker, with a general 0.25-0.75 inch prediction.
A brief burst of snow is possible as precipitation ends from west to
east Wednesday, and noticeably colder air arrives from the west,
although the vast majority of measurable precipitation is expected
to fall prior to any mixed precipitation or changeover. Little to
no impacts are expected from such snow showers with antecedent warm
ground and air temperatures in the mid to upper 30s or higher as
precipitation tapers off. Wednesday`s high temperatures mainly in
the 40s will be early in the morning before cold advection takes
over during the day. The system`s southern, potent vort max will
sprint across the region during the afternoon, holding westerly
winds gusting to 25-35 MPH...with wind chills dropping to near 20F
by sundown.
Wednesday night through Sunday...
The rather potent upper trough supporting the departing mid-week
system will cross the region quickly around the Wednesday evening
timeframe. In its wake strong polar surface high pressure will
build in from the central Plains on robust westerly breezes...
likely bringing the region`s coldest night in 10 days, With a few
northwest counties possibly dropping into the upper teens. Below
normal temperatures will continue Thursday amid dry conditions with
coldest spot only rebounding to around 32F...before the progressive
pattern backs diminishing winds to the south as the amplified
surface ridge advances east of the region.
The remainder of the week will feature steadier, often dry
conditions under an upper-level zonal pattern. The broad dome of
high pressure will slide off the Mid-Atlantic coast while extending
its axis back to the Gulf coast, blocking any significant moisture
despite several days of south-southwesterly return flow. Meanwhile
a strengthening baroclinic system will eject from Kansas to Ontario,
and drag it`s rather unsupported cold front towards and across
Indiana to end the week. Modest increases in precipitable water and
at best weak forcing will promote isolated rain showers through the
weekend and perhaps a few wet nocturnal snow showers. Temperatures
will remain slightly above normal under the zonal pattern. The
normal max/min at Indianapolis through the long term is 45/30.
&&
.Aviation...(00Z TAF Issuance)
Issued at 636 PM EST Sun Nov 27 2022
Impacts:
* IFR to MVFR ceilings to persist through Monday morning
* NW winds diminishing to around 10 kts this evening
* Patchy fog possible around sunrise at KHUF and KBMG
Discussion:
Low pressure has moved off to the northeast with lingering moisture
and clouds remaining across Indiana. Current observations show
ceilings hovering between IFR and MVFR levels across the region.
These conditions are expected to persist through the overnight hours
and into Monday morning as high pressure moving in works to trap
moisture and low clouds near the surface. Expect a gradual
improvement of ceilings from MVFR to VFR late morning into early
afternoon Monday.
Fog is a possibility toward sunrise, especially if any location
clears out briefly; however confidence is low in widespread fog
developing. KHUF and KBMG have the highest chances at seeing any fog
and visibility reductions overnight. Higher confidence exists
however in low stratus persisting at TAF sites through the morning
hours.
Winds have turned westerly to northwesterly across all TAF sites
this evening and have already began a diminishing trend. Winds will
hover around 10 kts over the next few hours before dropping off even
further towards sunrise. With high pressure approaching, would not
be surprised to if KHUF and KBMG went almost calm by sunrise. Winds
will turn southerly by Monday afternoon at all TAF sites as high
pressure slides east of the region.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...CM
Short Term...Ryan
Long Term...AGM
Aviation...CM